1. Technical Field of the Invention
The present invention relates broadly to the field of biomedical transducers and, more particularly, to a passive sensor monitoring the heart of a fetus.
2. Related Art and Problem to be Solved
Conventional fetal heart monitoring sensors are described in U.S. Pat. Nos. 4,471,200, 4,784,154, 5,209,237, and 5,524,631. Several known fetal heart sensors utilize a belt having one or more sensor stations thereon. Common shielding is used for all the sensor stations. However, in many instances, the common shielding crackles and moves thereby causing noise and interference of the detected fetal heart acoustic signal.
Some prior known heart monitoring sensors utilize a layer of RTV silicone to function as external pads that provide electrical isolation of the patient with respect to the belt sensor assembly. However, the RTV silicone layer is susceptible to chipping thereby reducing the electrical isolation between the belt sensor assembly and the patient.
Accordingly, it is an object of the present invention to provide a fetal heart monitoring sensor that substantially eliminates the problems associated with known fetal heart monitoring sensors.
Other objects and advantages of the present invention will in part be obvious and will in part be apparent from the specification.